Alright, I am trying to fix a few things on my old man's '95 1 ton 5 speed. The one I'm working on has me stumped. The tach and speedo stopped working, the alternator appears to not be fielding so it's not charging, and the air bag light is staying on.

I've heard this could be the CPS but I heard if it's bad, the WTS light won't come on. This one is coming on. My dad had picked up a new Cummins CPS so I threw it on and gapped it to .049 with non-metallic guages.

Fired the truck and no change.

I've heard that if metallic feeler guages are used, it can ruin the CPS. When I pulled the new CPS out of the box, one of the wire clamps was stuck to the actual sensor (magnetically). Could this have ruined the part before I even had the chance to swap them?

Next I've heard the problem could be the PCM. I'm really hoping this is not the case but what should I be checking to diagnose?

Any other things to take a look @?

 

PCMs rarely go bad. Check the continuity between all 3 ESS (engine speed sensor, 12 valves don't have a CPS) wires to the PCM.

Of course check all fuses well, sometimes visual inspection isn't good enough.
A check in place fuse checker at under $10 is a good investment.

 

Throwing parts at truck is financially unsound.
Yes on wire checks suggested.
Yes on critical fuse inspections.
Get codes read to give us a clue on what computer is seeing wrong.